Fuse holder having indicator means

ABSTRACT

Fuse holder for utility power line comprises a cylindrical housing having a closed end through which the fuse extends. One conductor is connected to the fuse at this closed end. An indicator sleeve is slidably mounted in the housing for sliding movement between a retracted position, in which it is within the housing, and an extended position, in which it projects substantially beyond the housing. A spring normally biases the sleeve to the extended position. In use, the spring is compressed and the sleeve moved to its retracted position. A second conductor is secured to the sleeve and to the fuse so that if the fuse is blown, the spring moves the sleeve to its extended position.

United States Patent 1191 Dola 11] 3,868,618 [451 Feb. 25, 1975 FUSEHOLDER HAVING INDICATOR MEANS 52 u.s.c1 337/206, 337/241,337/244 511111.01; ..H0lh 85/30 [58] Field ofSearch 337/173,17s, 194, 206,

[5 6] References Cited UNITED STATES PATENTS 5/1943 Triplett 33.7/24l X2/1967 Lindell 337/241 X Primary Examiner-JD. Miller [57] ABSTRACT Fuseholder for utility power line comprises a cylindrical housing having aclosed end through which the fuse extends. One conductor is connected tothe fuse at this closed end. An indicator sleeve is slidably mounted inthe housing for sliding movement between a retracted position, in whichit is within the housing, and an extended position, in which it projectssubstantially beyond the housing. A spring normally biases the sleeve tothe extended position. In use, the spring is compressed and the sleevemoved to its retracted position. A second conductor is secured to thesleeve and to the fuse so that if the fuse is blown, the spring movesthe sleeve to its extended position.

6 Claims, 7 Drawing Figures 1 FUSE HOLDER HAVING INDICATOR MEANSBACKGROUND OF THE INVENTION This invention relates to fuse holders forfuses of the type used in utility power lines to fuse a transformer orfor other purposes. Fuse holders of this type must be sturdy and durablesince they are continuously exposed to the elements and must functioneffectively for long periods of time. Fuse holders of this type areusually designed to provide a visual indication if the fuse has blown sothat the utility worker can determine whether or not a particular fusehas been blown without climbing the utility pole near which the fuse isinstalled.

Most of the fuse holders which are presently used are satisfactory froma functional standpoint but they are relatively heavy and complicatedand require heavy duty mounting hardware for their installation. Theyare also relatively high-priced because of their complexity and theinstallation is a time consuming operation.

The instant invention is specifically addressed to the problem ofproviding a relatively simple and light weight fuse holder which can bereadily installed on a utility line and which is capable of withstandingcontinued exposure to a variety of adverse weather conditrons.

It is accordingly an object of the invention to provide an improved fuseholder for fuses of the type used on power utility lines. A furtherobject is to provide a light weight fuse holder which can beconstructed, for the most part, of durable plastic materials. A furtherobject is to provide a light weight fuse holder which can be installedwithout the requirement of relatively heavy duty mounting brackets orthe like. A further object is to provide a fuse holder having improvedindicator means for indicating whether or not the fuse has blown.

These and other objects of the invention are achieved in a disclosedembodiment thereof which is briefly described in the foregoing abstract,which is described in detail below, and which is shown in theaccompanying drawing in which:

FIG. 1 is a side view, partially in section, of a fuse holder inaccordance with the invention having an unblown fuse installed therein.

FIG. 2 is a sideview of a fuse of a type which is adapted to beinstalled in the fuse holder of FIG. 1.

FIG. 3 is a fragmentary sectional view of the lower portion of the fuseholder of FIG. 1 showing the positions of the parts after the fuse hasblown.

FIG. 4 is a view taken along the lines 4--4 of FIG. 1.

FIG. 5 is a schematic view showing the manner of installing a fuse for atransformer using a fuse holder in accordance with the invention, thisview showing the appearance of the fuse holder when the fuse is unblown.

FIG. 6 is a view similar to FIG. 5 but showing the appearance of thefuse holder after the fuse has been blown.

FIG. 7 is a schematic view showing the manner in which a fuse holder inaccordance with the invention can be used to fuse a temporary feederline extending from a main power line.

The disclosed embodiment of the invention is adapted to receive a fuseof the type shown at 2 (FIG. 2) comprising a generally cylindrical body4 having a nut 6 on its upper end which has a radially extending collar7. The contact surface for one external conductor is provided at theupper end ofthe fuse and is shown at 8. The body 4 contains the fusablemetal and a flexible conductor 10 is crimped onto, and extends from, thefusable material and from the lower end of the fuse. The fusable elementand the conductor 10 are able to withstand a substantial tensile forcebut if the fuse is blown, the conductor 10 can be pulled, or will fall,downwardly.

A preferred form of fuse holder 12 in accordance with the inventioncomprises a cylindrical housing generally indicated at 14 having a capmember 16 assembled to, and mounted on, its upper end to close the upperend. A relatively thin walled cylindrical body 18 extends from the capmember and is secured to the cap by means of an annular flange 20 towhich the body is bonded or otherwise secured. Cap member 16 has acentral cylindrical boss 22 which has a flat upper surface 26 and anaxial opening 24 which communicates with the interior of the housing.

The fuse 2 is installed in the housing by passing the body portion 4thereof through the opening 24 until the collar 7 is against the surface26. A cap nut 28 is then assembled to the cap member 16 by means ofcomplementary threads 30 provided on the extension 22 and the interiorof the cap nut. The cap nut is of plastic, as are the cap member 16 andthe body 18, however, a rigid conductor rod 30 is axially mounted in thecap nut 28 so that when the cap nut is threaded tightly onto the capmember, the lower end of the rod 30 will be electrically connected tocontact surface 8 of the fuse. Rod 30 extends upwardly from the cap nutand is connected by means ofa conventional clamp 32 to the stirrupportion 34 of a hot wire clamp 36 (see FIG. 5).

A relatively thin walled indicator sleeve 40 is slidably contained inthe lower portion of the cylindrical portion 18 and is movable between aretracted position, in which it is substantially fully retracted in body18, to an extended position as shown in FIG. 3. When the indicatorsleeve is in its extended position, a substantial portion of its lowerend 46 projects below and beyond the lower end of the body 18. Indicatorsleeve 40 is guided during movement between its two extreme positions,and the limits of these positions are defined, by pins 44 which aremounted in the body 18 and which extend through axial slots 42 in theindicator sleeve.

The lower portion 38 of the indicator sleeve is arcuate as shown and hasa connecting device 48 mounted on its lower end. This connecting devicecomprises a cylindrical member having a reduced diameter section 50 onits lefthand end which is provided with an opening through which theconductor 10 extends. The end of the conductor 10 is clamped against theshoulder 49 by means ofa nut 52 which is threaded on this reduceddiameter portion. The adjacent larger diameter portion 54 oftheconnecting device extends slidably through an opening in the indicatorsleeve and through an opening in an arcuate bracket 56. The bracket hasintegral mounting feet 58 which are secured to the external surface ofthe lower portion 46 of the sleeve by fasteners 60. A nut 62 is threadedonto the end of the larger diameter portion 54 of the connecting deviceand a washer 64 is interposed between this nut and the bracket 56. Theexternal conductor is connected to connecting device 48 by beinginserted through a transverse opening in the larger diameter portion 54which is normally between the surface of the lower end of the sleeve andthe internal surface of the bracket. The nut 62 is then tightened todraw the connecting device rightwardly as viewed in the drawing untilthe conductor 55 is firmly pressed against the opening in the connectingdevice.

A compressable spring 66 is interposed between the upper end of theindicator sleeve and the downwardly facing shoulder 68 of the flange 20of cap member 16. This spring normally biases the indicator sleeve toits extended position as shown in FIG. 3 but the spring can becompressed as shown in FIG. 1 when the sleeve is moved to its retractedposition.

In use, the fuse is installed by passing it through the opening 24,asexplained above, and threading the cap nut 28 onto the cap member 22.Thereafter, the sleeve is moved upwardly and into the cylindrical body18 and the spring 66 is compressed. The lower end of theflexibleconductor is then clamped to the connecting device48 and thefuse holder is then installed between the stirrup 34vand the externalconductor 55. When the fuse is blown, the indicator sleeve is biased toits extended position to'provide a visual indication of the condition ofthe fuse.

Fuse holders in accordance with the invention are adapted to be-used tofuse a transformer 72 mounted on a utility pole. 74 andconnected to amain power line 70. As shown inFIG. 5, the fuse holder and fuse can beinstalled with only a conventional hot wire clamp 36 and the auxiliaryclamp 32 which connects the stirrup to the conductor 30in the cap nut28. As illustrated by FIG. v6, the extended indicator sleeve gives animmediate indication that the fuse has been blown.

The easily installed and the light weight hardware shown in FIGS. 5 and6 can be used with a fuse holder in accordance with the invention forthe reason the fuse holder itself is not heavy and bulky. Most of theparts of the fuse holder can be produced of a durable weather resistentand strong plastic such as a polycarbonate and the only metal partsrequired in a'fuse holder-in accordancewith the invention are theconductor 30, the connecting device 48, and the spring member 56although .the indicator sleevev can be of metal if desired.-

- to the ends of the feeder lines and are connected to the main lines 76adjacent to the utility pole. Again, relatively simple connecting clamps(not specifically shown in FIG. 7) can be used to connect the conductorsex-- tending from the fuse to the lines 76, 78.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only.

What is claimed'is:

1. A fuse holder adapted for use with a current limiting fuse, said fusebeing cylindrical and having a radially extending collar at one endthereof, a conductive contact area centrally located with respect tosaid collar, and a flexible conductor extending from the other endthereof, said fuse holder comprising:

a generally cylindrical housing having a closed end and an open end,said closed end having a flat ex-' ternal surface and an axiallyextending opening extending therethrough and communicating with theinterior of said housing,

a cap member removably mounted on said closed end, said cap memberhaving a cap member conductor extending axially therethrough,

an indicator sleeve concentrically and slidably mounted on said housing,said indicator sleeve having a first end which is proximate to saidclosed end of said housing and having a second end which is remote fromsaid closed'end, said sleeve being movable between a retracted position,in which said second end thereof is adjacent to said open end of saidhousing, and an extended position, in which said second end is remotefrom said open end and portions of said sleeve extend substantiallybeyond said housing,

means for securing said flexible conductor to said sleeve and forsecuring an external conductor to said sleeve, and compressibleresilient means interposed between said first end of said sleeve andsaid closed end of said housing whereby,

upon inserting said fuse through said opening and locating said collaron said surface, assembling said cap member to said housing, moving saidsleeve to saidretracted position, and securing saidflexible conductor tosaid sleeve, said sleeve will be retained in'said retracted position bysaid fuse, and if said fuse should fail, said sleeve will be movedtosaid extended position under the influence of said resilient meansthereby to provide a visual indication of the failure of said fuse.

2. A fuse holder as set forth in claim 1, said indicator sleeve beinginside of said housing.

3. A fuse holder as set forth in claim 2, said closed end having a capthereon, said opening extending through said cap. a

4. A fuse holder as set forth in claim 2, said closed end having anaxially extending cylindrical boss and having a cap member threaded ontosaid boss, said opening extending through said cap 'member and throughsaid boss, said collar. on said fuse being adapted to be clampedbetween'said cap and said boss.

5. A fuse holder as set forth in claim 4, said cornpressible resilientmeans comprising a coil spring.

6. A fuse holder in combination with a current'limiting fuse, said fusecomprisinga cylindrical member having a radially extending collaradjacent to one end thereof and a first conductor extending-from theother end of said fuse, said fuse having a contact surface centrallylocated with reference to said collar at said one end, said fuse holdercomprising:

a generally cylindrical fuse holder housing having a closed end and anopen end, said closed end having a flat external surface extendingnormally of the axis of said housing and having a central opening, saidfuse being disposed'in said housing with said collar on said flatsurface and with said fuse body means for limiting axial movement ofsaid first end of said indicator body past said open end ofsaid housmg,said indicator body being normally retained in said housing by said fuseand said first conductor against the biasing force of said resilientmeans whereby, upon failure of said fuse, said indicator body is movedto an extended position under the influence of said resilient meansthereby to indicate failure of said fuse.

1. A fuse holder adapted for use with a current limiting fuse, said fusebeing cylindrical and having a radially extending collar at one endthereof, a conductive contact area centrally located with respect tosaid collar, and a flexible conductor extending from the other endthereof, said fuse holder comprising: a generally cylindrical housinghaving a closed end and an open end, said closed end having a flatexternal surface and an axially extending opening extending therethroughand communicating with the interior of said housing, a cap memberremovably mounted on said closed end, said cap member having a capmember conductor extending axially therethrough, an indicator sleeveconcentrically and slidably mounted on said housing, said indicatorsleeve having a first end which is proximate to said closed end of saidhousing and having a second end which is remote from said closed end,said sleeve being movable between a retracted position, in which saidsecond end thereof is adjacent to said open end of said housing, and anextended position, in which said second end is remote from said open endand portions of said sleeve extend substantially beyond said housing,means for securing said flexible conductor to said sleeve and forsecuring an external conductor to said sleeve, and compressibleresilient means interposed between said first end of said sleeve andsaid closed end of said housing whereby, upon inserting said fusethrough said opening and locating said collar on said surface,assembling said cap member to said housing, moving said sleeve to saidretracted position, and securing said flexible conductor to said sleeve,said sleeve will be retained in said retracted position by said fuse,and if said fuse should fail, said sleeve will be moved to said extendedposition under the influence of said resilient means thereby to providea visual indication of the failure of said fuse.
 2. A fuse holder as setforth in claim 1, said indicator sleeve being inside of said housing. 3.A fuse holder as set forth in claim 2, said closed end having a capthereon, said opening extending through said cap.
 4. A fuse holder asset forth in claim 2, said closed end having an axially extendingcylindrical boss and having a cap member threaded onto said boss, saidopening extending through said cap member and through said boss, saidcollar on said fuse being adapted to be clamped between said cap andsaid boss.
 5. A fuse holder as set forth in claim 4, said compressibleresilient means comprising a coil spring.
 6. A fuse holder incombination with a current limiting fuse, said fuse comprising acylindrical member having a radially extending collar adjacent to oneend thereof and a first conductor extending from the other end of saidfuse, said fuse having a contact surface centrally located withreference to said collar at said one end, said fuse holder comprising: agenerally cylindrical fuse holder housing having a closed end and anopen end, said closed end having a flat external surface extendingnormally of the axis of said housing and having a central opening, saidfuse being disposed in said housing with said collar on said flatsurface and with said fuse body extending through said opening andcoaxially into said housing, said housing having external threads onsaid one end, a fuse holder cap of insulating material threaded ontosaid closed end, said cap having a second conductor extending axiallytherethrough, said conductor being in electrical contact with saidcontact surface, an indicator sleeve slidably and concentrically mountedin said housing, said sleeve having a first end which is proximate to,but spaced from, said closed end of said housing and having a second endwhich is remote from said closed end, said first conductor being securedto said indicator sleeve adjacent to said second end, means forconnecting on external conductor to said first conductor, compressedresilient means interposed between said first end of said indicatorsleeve and said closed end of said housing, said resilient means biasingsaid indicator body towards said open end of said housing, and means forlimiting axial movement of said first end of said indicator body pastsaid open end of said housing, said indicator body being normallyretained in said housing by said fuse and said first conductor againstthe biasing force of said resilient means whereby, upon failure of saidfuse, said indicator body is moved to an extended position under theinfluence of said resilient means thereby to indicate failure of saidfuse.